Food allergy accommodation policies in colleges and universities: an investigation using organizational culture as a theoretical framework

A sequential explanatory mixed methods design (questionnaire and interview) was used to examine current food allergy accommodation practices, policies and procedures in colleges and universities. Also, organizational culture of college and university foodservice operations using the Competing Values Framework was investigated. A web-administered questionnaire was developed based on previous literature, and distributed to a national sample of foodservice professionals who were current members of the National Association for College and University Food Services. Seventy-six questionnaires (22.2% response) were used for analysis. Questionnaire results were analyzed using descriptive statistics, ANOVA, pooled sample t-tests and population proportion tests. Interview guides were developed based on questionnaire data and interviews (n=11) were conducted with a subsample of the questionnaire participants. Fifty-five (74%) questionnaire participants reported food allergy accommodation policies were in place at the departmental level and 25 (34%) reported policies at the institutional level. Departmental level policies were more prevalent at public institutions in comparison to private institutions; and more prevalent among contract-managed foodservice operations in comparison to self-operated. Interview data revealed considerable variation in approaches to food allergy accommodations irrespective of policy presence. Clan culture, characterized by a nurturing, environment emphasizing personal relationships, was the most prominent culture among represented foodservice operations. Due to low statistical power, significant differences in food allergy accommodation policies and practices were not detected based on organizational culture type, however interview data suggested organizational culture may impact accommodation efforts

Numerical and experimental study of steady and unsteady mixed convection flow in a cubical open cavity with the bottom wall heated

En aquest estudi s'analitzen els experiments i simulacions numèriques del flux de convecció mixta en una cavitat cúbica situada a la part inferior d'un canal quadrat. Els nombres de Reynolds en funció de la velocitat mitjana del flux i l'amplada del canal estan en el rang 100≤Re≤1500 i el nombre de Richardson varia entre 0.1≤Ri≤10. La tècnica PIV s'ha utilitzat per a les mesures en un canal d'aigua. Simulacions numèriques Tridimensionals s’han dut a terme amb un codi de volums finits de segon ordre considerant l'aproximació de Boussinesq ja que, per les condicions experimentals utilitzades, la variació de les propietats físiques amb la temperatura no té influència significativa en la topologia general de flux. Per 100≤Re≤1500 i Ri≤0.1 el flux és estacionari i consisteix en un remolí situat a l’interior de la cavitat cúbica que mostra velocitats majors a mesura que augmenta el nombre de Richardson. El flux és no estacionari a Re = 100 i Ri = 10. Prop de les parets laterals es produeixen, de forma alternada, ejeccions de flux, des de l’interior de la cavitat cap al canal, mentre que el flux entra a la cavitat des del canal a través de la part central de la cavitat. S'ha utilitzat una tècnica de mostreig condicional per elucidar l’estructura mitjana de l'evolució del flux turbulent a Ri = 10. S'ha trobat que les ejeccions de flux persisteixen durant tot el rang de Reynolds analitzat. Els números de Nusselt calculats estan d'acord amb els de les correlacions reportades a la literatura, vàlides per cavitats bidimensionalsEn este estudio se analizan los experimentos y simulaciones numéricas del flujo de convección mixta en una cavidad cúbica situada en la parte inferior de un canal de sección cuadrada cuadrado. Los números de Reynolds en función de la velocidad media del flujo y la anchura del canal están en el rango 100≤Re≤1500 y el número de Richardson varía entre 0.1≤Ri≤10. La técnica PIV se ha utilizado para las medidas en un canal de agua. Se han llevado a cabo simulaciones numéricas tridimensionales con un código de volúmenes finitos de segundo orden, considerando la aproximación de Boussinesq ya que, en las condiciones experimentales utilizadas, la variación de las propiedades físicas con la temperatura no tiene influencia significativa en la topología general de flujo. En los rangos 100≤Re≤1500 y Ri≤0.1 el flujo es estacionario y consiste en un remolino situado en el interior de la cavidad cúbica que muestra velocidades mayores a medida que aumenta el número de Richardson. El flujo es no estacionario a Re = 100 y Ri = 10. Cerca de las paredes laterales se producen de forma alternada eyecciones de flujo, desde el interior de la cavidad hacia el canal, mientras que el flujo entra en la cavidad desde el canal a través de la parte central de la cavidad. Se ha utilizado una técnica de muestreo condicional para elucidar la estructura media de la evolución del flujo turbulento a Ri = 10. Se ha encontrado que las eyecciones de flujo persisten durante todo el rango de Reynolds analizado. Los números de Nusselt calculados están de acuerdo con los de las correlaciones reportadas en la literatura, válidas para cavidades bidimensionales.In this study we analyze experiments and numerical simulations of steady and unsteady mixed convection flow in a cubical cavity located at the bottom of a square channel. The Reynolds numbers based on the mean flow velocity and the channel width are in the range 100≤Re≤1500 and the Richardson numbers vary within 0≤Ri≤10. Particle Image Velocimetry has been used for the measurements in a water channel. Three-dimensional direct numerical simulations have been carried out with a second order finite volume code considering the Boussinesq approximation since, for the experimental conditions considered, the variation of the physical properties with temperature has no significant influence on the overall flow topology. For 100≤Re≤1500 and Ri≤0.1 the flow is steady and it consists in a single roll that exhibits larger velocities as the Richardson number is increased. An unsteady periodic flow is found at Re=100 and Ri=10. Alternate flow ejections from the cavity to the channel occur near the lateral walls while the flow enters the cavity from the channel through the central part of the cavity. A conditional sampling technique has been used to elucidate the evolution of the mean unsteady turbulent flow at Ri=10. It has been found that the alternate flow ejections persist for all the Reynolds analyzed. The computed Nusselt numbers are in general agreement with a previously reported correlation, valid for two dimensional cavities of different aspects ratios

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Using Wireless Communications To Enable Decentralized Analysis and Control of Smart Distribution Systems

The smart grid is a multidisciplinary approach that aims to revolutionize the whole electricity supply chain including generation, transmission and distribution systems in order to overcome the multiple challenges currently facing the electric power grid. The smart grid could be seen as a modern electrical power grid in which information as well as electricity flows among all nodes in the system, information is continuously collected, processed and hence used to control and coordinate the different system components such as distributed generation (DG) units, capacitor banks, voltage regulating transformers, etc. Therefore distributed intelligence and two-way data communication links are essential components in implementing the smart grid vision. There are numerous research efforts that focus on implementing the smart grid vision in electrical power distribution systems, most of which only target one aspect of the distribution system control and operation, e.g. a control system for voltage control, another one for DG control, a third one for protection, etc. The coexistence of such control strategies in a distribution system raises some concerns about their overall performance, their interactions with the other control strategies, and whether these control systems can adapt to changes in distribution system connectivity. In this PhD thesis we try to address these issues by proposing an implementation of the smart grid vision for distribution systems that provides an integrated design of power systems, communication systems and control strategies. A unified and flexible framework that incorporates all the different aspects of distribution system control and operation is proposed. Distributed processing units equipped with wireless communication capabilities are used to continuously process the local data along with the data received from other nodes and forward the results to neighboring nodes in the system, which in turn process the received data and share the results with their neighbors. Consequently, changes in any of the system components (load values, status of DG etc.) are taken into account in the calculations as soon as they occur, and the results are forwarded to relevant nodes in the systems. This way the information “propagates” throughout the system resulting in a seamless control and coordination among all the system components. Simulation of the electrical power distribution and the communication systems reveal the effectiveness of the proposed framework to control and coordinate multiple capacitor banks, DG units and voltage regulating transformers with changing load levels. It also reveals the potential of the proposed framework to operate in real-time by combining the real-time measured quantities with computer analysis in order to control the different system components within the time frame of normal non-emergency operating conditions. An experimental setup is built and used as a test bed for the proposed framework in order to assess the performance of the different ideas and techniques proposed in this thesis

The Effect of Age on Corneal Topographic Indices, Keratometry and Visual Acuity After Combined Intrastromal Corneal Ring Segment (ICRS) Implantation and Corneal Crosslinking

We aimed to assess age-related changes in corneal topographic indices, keratometry and visual acuity after sequential intracorneal ring segment implantation (ICRS) and crosslinking (CXL). This was a retrospective matched case-control series including 26 eyes of patients ≤18 years as the cases and 26 eyes of adult patients as control. All eyes received ICRS+CXL for progressive keratoconus. Eyes were matched regarding the keratoconus parameters and the treatment (type, number and thickness of ICRS). Data was analyzed for refractive and topographic values [uncorrected and corrected distance visual acuity (UDVA; CDVA) sphere; cylinder; spherical equivalent; maximum keratometry (Kmax); flat keratometry (Kflat); steep keratometry (Ksteep); all 7 pentacam topographic indices] preoperatively and one year postoperatively. Preoperatively, there was no significant difference for any refractive, clinical or topographic parameters between the groups except for vertical asymmetry. After one year, children had a significantly higher improvement in Ksteep (3.05D) than adults (2.10D; P=0.036) and a trend to significance for Kflat (2.7D compared to 1.78D, respectively; P=0.081). UDVA improved by 4.3 ETDRS lines in children compared to 3.3 ETDRS lines in adults and CDVA improved by 1.7 ETDRS lines in children compared to 1.2 ETDRS lines in adults, but with no statistical significance. The effects on keratometry indicated that corneal response after ICRS and CXL for keratoconus is more pronounced in young patients than adults. This assumption is also supported by functional improvement and by the fact that a few eyes (5) of some very young patients (<13years) showed highly remarkable improvements after surgery (higher than any adult eye)

Chronic ocular GVHD: limbal and conjunctival stem cell allografts from the same hematopoietic stem cell donor

Letter to the edito

Central retinal vein occlusion in young population: risk factors and outcomes

ObjectiveTo evaluate the risk factors and outcomes of central retinal vein occlusion (CRVO) in young patients (< 40 years).MethodsIn this retrospective monocentric case series, we included young patients (<40 years) with CRVO. Patients’ medical files were analyzed focusing on demographic characteristics, suspected risk factors, ophthalmic work-up, visual acuity (VA), treatment, and outcomes.ResultsA total of 54 eyes of 52 patients were included. Central retinal vein occlusion was considered idiopathic in 13 patients (25%). The main risk factors identified were ocular hypertension (20.4%), inflammation (20.4%), high blood pressure (14.8%), and coagulation abnormality (11.1%). Final VA was lower in patients with high blood pressure and inflammation when compared to patients with no risk factor (p = 0.03 and 0.04, respectively). Intravitreal injections were needed in 23 eyes (42.6%) and 19 eyes (35.2%) received panretinal photocoagulation treatment.ConclusionCentral retinal vein occlusion is frequently associated with risk factors in young patients (75% of patients). In addition to the usual factors found in older patients, such as ocular hypertension and high blood pressure, coagulation abnormality and inflammation were also among the risk factors identified. Young patients with CRVO should be evaluated for the presence of risk factors and patients with high blood pressure or inflammatory findings should be followed carefully since they have a worse outcome